Duplex brake-cylinder.



W. V. TURNER.

DUPLEX BRAKE CYLINDER.

APPLICATION FILED PEB. Z7, 1907. v

` -Patented Oct. 27, 1908.

,3 o 2/4 a PJ? INVENTOR- lll/III III/II WITNESSES Atty.

UNITED STATES PATENT OFFICE.

AIR BRAKE COMPANY, OF PITTSBURG, VANIA.

Specification of Letters Patent.

PENNSYLVANIA, A CORPORATION OF PENNSYL- DUPLEX BRAKE-CYLINDER. i

Patented Oct. 27, 1908.

Application filed February 27, 1907. Serial No. 359,605.

T all whom 'it may conce/rn:

Be it known that I, Viv/'ALTER V. TURNER, a A citizen of the UnitedStates, residing at Edgewood, in the county of Allegheny andState ofPennsylvania, have invented new and useful Improvements in DuplexBrake-Cylinders, of whichl the following is a s eciiication.

This invention relates to bra :e cylinders A adapted to be operated byiiuid pressure,

slack in" the bra such as compressed air, and more particularly to adouble brake cylinder apparatus, wherein one cylinder andpistoia-usually a small one, is em` loyed for first taking up the erigging and a plying the brake shoes to the vwheels with ligiitpressure, and then the luid pressure is a plied to a larger brakepiston, which is loied to the small piston, or its connections, by aclutch device, for exertingthe iinal .heavy pressure upon the brakeshoes .l

The principal object of my present invention is to provide an improvedlocking means for attaching or clutching the large piston to the smallpiston, or its connections, after the latter has made an outwardmovement, whereby only a very short stroke of the large piston isnecessary to apply the brakes with fullpower after the small piston hasmoved lthe brake shoes up against the wheels.

VVhile'my invention is especially adapted' for use in connection withthat form of double brake cylinder wherein the small cylinder and pistonis mounted on the large piston, it is not necessarily limited thereto,but may also be applied in connection with other l forms. of duplex ordoublerbrake cylinder apparatus.

In the accompanying drawing;.Figure 1 is a longitudinal section oi aduplex brake cylinder apparatus of the type wherein the small cylinderand piston are mounted on the large piston, and illustrates one form ofmy invention which is applicable thereto; Fig. 2 a transverse sectiontaken on the line of Fig. 1; Fig. 3 an end view of the smaller cylinder,which is mounted onand forms a part of the large piston Fig. 4 a planview of the end of the same; and Figs. 5 and 6, side and end viewsrespectively of one oi the locking pawls which are carried by the largebrake piston.

According to the construction shown in the drawing7 the mai n or largebrake cylinder 7 contains the largo piston 8, on which is mounted theextension l0, Aforming a cylinder I I for the small brake piston 9,which Operates -the hollow piston rod 11 adapted to contain a push barfor connection to the brake rigging.

he release spring 12 acts to return one or both pistons to the innerposition when the iluid under pressurel is exhausted from the brakecylinders.

The large piston head 8 is provided with a port 16 and a seat 17surrounding the same. for engaging a gasket on the head of the cylinderaround the passage or port 14 for su plying and releasing Huid to andfrom t e smallcylinder on the face .of piston 9. An additional port, orpassage, 15 is employed for supplying iiuid directly to the face of thelarge piston 8, in cylinder 7, and any suitable or preferred means maybe used for controlling the-supply of fluid to the port 15 and the largecylinder after the piston ofthe small cylinder has moved outward to takeup the slack of the brake rigging.

In Aorder to lock the Llarge piston to the small piston, or itsconnections, when the ,large piston begins to move outward, and afterthesmaller piston has made its outward stroke, a pawl and ratchet mechanismmay be provid ed, one part being operated by the movement of one pistonand' the other part being carried bythe other piston. As shown in thedrawing, such a structure may comprise one or more pawls, 20, pivotallymounted betweenl lugs 19, on. the cylinder extension 10 of the largepiston 5, while the small piston is provided with a cylindricalextension 21 having ratchet teeth 13 formed thereon for engaging withsaid pawls.

Any suitable 'means may be employed for throwing the pawls into and outof engagement at the roper times, but I prefer to provide a gui e whichmay be conveniently formed as casing 18, covering the end of thecylinder, and having guide surfaces 22 and 23 properl arranged to beengaged bythe correspon ing bearing portions 24 and 25 of the pawls 20,so that the pawls are forcibly thrown outward to engage the ratchetteeth when the large piston begins its outward movement, and areautomatically released from such engagement when the piston is returnedto its normal release position.

When air, or other Huid under pressure, is

In this manner, the maximum braking power.

the slack and bring the brake shoes against the wheels with' theexpenditure of only a small amount .of fluid, necessary to till thesmall cylinder; then when' the fluid is adoutward upon its pivot to enage the ratchet teeth 1 3, carried by the smal piston, so that theclutch mechanisme crates to Aloch the large piston to the sma ler andapply lull power ofthe fluid acting upon the area of the arge piston toforce the brake shoes against the wheels, but with the consumption ofonly a small volume of fluid, since the large piston travels but a1short distance in. its cy inder.

is secured with a minimum volumeof Huid, and a great saving is therebyeffected in the amount of air or other fluid under pressure required tooperate the brake system.

When the fluid is released fromthe brake cylinder, the spring l2 returnsthe pistions to their inner. positions,l and as the parts 250i the pawls2O en age their corresponding guide surfaces 23 t e pawls areautomatically released from engagement withv the ratchet teeth. 1

It will now be seen that my improvement provides a simple, compact anddurable construction for automatically locking the pistons togetherafter the small piston has made its outward stroke and upon theinitialmovement of the` large piston, thereby greatly economizing the amount offluid necessary for braking purposes.

Having now described lily-invention, what I claim as new and desire tosecure by Letters Patent, 1s:

1.' A duplex brake cylinder, comprising av large cylinder` and piston, asmall cylin and piston mounted on the large piston, and means forlocking the large piston to the smaller after the latter has movedoutward in its cylinder each piston having means for supplying i'luidunder pressure thereto.

. 2. A duplex brake cylinder, comprisin a larve cylinder and piston, asmall cylin er an piston mounted on the large piston, and a lockingmechanism for connecting the large piston to the small piston eachpiston having means for supplying fluid underl pressure thereto.

3. A duplex brake cylinder, comprising a large cylinder, a pistontherein carr ing a smaller cylinder, a piston in said smal cylinscarse.

piston to the smaller after theatter has made an outward strokeeachpiston having `means for supplying iiuid underpressure thereto;`

` 4'. A duplex brake cylinder, comprisin a large cylinder and piston, aysmall. cylin er anr piston mounted on the large piston,`v and ya,clutch device operating upon' theqinitial movementof fthelarge piston`tolock the same to transmit movement to the small piston.

'5: ifi duplex brake cylinder, comprising a auf piston mounted on thelarge piston, and locking means carried by the lar e piston forconnecting'thesame to the smalplston.

6. A duplex brakecylintler, comprisin a large cylinder and piston, asmall cylinder an and normally held out of enga ement, and meansoperating upon'1 the initia movement ofthe large piston for forcing saidlocking mechanism into engagement. r, '7

7. A duplex bra e cylinder, `comprising a c er large cylinder andpiston, a small-cylin an( piston mounted on the large piston, lock'- ingpawls for clutching thelarge piston to the sma ler, and means operatingupon the outward movement of the large piston for throwing said awls'mtoaction.

8. A upleX brake cylinder, comprising a` lar e cylinder and piston, asmall *cylinder an piston, locking pawls for connecting said,-

pistons-together, and means o erating upon largecylindcr and piston, asmall cylinder- Idar, anda clutch device for lookin thelarge y vabpiston mounted on the large piston,'lock i c mechanism carried by thelarger piston the outward movement of the arge piston to' cause saidpawls to engage, and upon the i'nward moyement to cause said pawls torelease. y j 9. A duplex brake cylinder, comprisinga lar e cylinderxandpiston, a small cyln er an piston, locking pawls for connecting saidistons together, a fixed guide having suraces for engaging said pawlsand causing the same to engage upon the outward vmovement of the largepiston and to release upon the inward movement. K i 1G. A du l'ex brakecylinder, comprising a large cylin er and piston, and a small cyhnderand piston, of locking means operated bythelarge piston for clutchingsaid large piston to the smaller after the latter has made its eutwardstroke. t

In testimony whereof .I have hereunto set my hand.

WVALTER -V. TURNER.

Witnesses R. F. Enum', J. B. MACDONALD.

